[Prithpal-Sooriya]

Explanation

Adds AssetsController.stale-balance-scenarios.integration.test.ts, an AssetsController-level integration suite covering all 12 stale-balance scenarios from the accounts API v6 integration decision doc (full and merge tables).

The suite boots the real AssetsController (with assetsAccountsApiV6: true) and mocks only the external boundaries, following the pattern of AssetsController.bsc-spam-token-filtering.integration.test.ts:

• HTTP APIs (Accounts API v6 + v2-supportedNetworks, tokens /v3/assets, prices /v3/spot-prices) are nocked from real captured responses in src/__fixtures__/stale-balance/api-responses/. Every fixture mutation is documented inline (balance doubling to model wallet movement between passes, occurrences stamping, chain omissions for RPC fallback).
• RPC / snap / lifecycle are exercised through mock messenger action handlers (NetworkController, SnapController, KeyringController, staking reads) and live events (AccountActivityService:balanceUpdated, AccountsController:accountBalancesUpdated, TransactionController:transactionConfirmed, KeyringController:unlock).

Scenario coverage (7 full + 5 merge): snap failure carry-over, skipped-asset last-amount copy, zero-seeding for never-seen visible assets, RPC fallback carry-over on failing balanceOf reads, disappearing zero-balance seeds, failed-fetch carry-over, fresh amounts on healthy fallback, event overlays, malformed-row handling, wrong-amount correction at the next full poll, snap-event overlay + refresh, and staked ETH on mainnet + Hoodi across an unlock lifecycle with a staking deposit.

Test plan

• yarn workspace @metamask/assets-controller run test
  • New suite: 12/12 scenarios pass
  • Full package suite passes
• yarn lint checks on the new files: oxlint and oxfmt clean
• yarn build (root, full monorepo type-check) passes

Notes for reviewers

• Fixture balance-row shape includes unit, required by the keyring API's Balance struct via strictMask (@metamask/keyring-api); the controller discards it downstream.
• Native ETH on Hoodi is keyed under the zero-address ERC-20 encoding (eip155:560048/erc20:0x0000000000000000000000000000000000000000) — the controller's documented fallback for EVM chains absent from its native-asset seed map, which excludes testnets.
• The Multicall3 aggregate3 fixture encodes the contract's real return shape — Result[] only, with no leading blockNumber (only aggregate/tryAggregate return one). An earlier draft of the fixture encoded (uint256, Result[]), which made every batch decode throw and silently fall through to single balanceOf calls; caught in review and fixed, so the scenarios exercise the batched read path. MulticallClient's decoder is correct as shipped — no product bug here.

References

• Recreates test(assets-controller): add stale-balance scenario integration tests for accounts API v6 #10535, which was accidentally opened from a personal fork that has since been deleted (deleting the fork auto-closed that PR). The changes are identical; this time the head branch lives on this repository so the Validate changelog diffs job can resolve origin/<head-ref> (the fork-PR limitation documented in that PR).

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've communicated my changes to consumers by updating changelogs for packages I've changed — no entries needed: test-only, non-consumer-facing changes (no-changelog label applied)
• I've introduced breaking changes in this PR and have prepared draft pull requests for clients and consumer packages to resolve them — N/A, no breaking changes

---

Note

Low Risk
Test-only additions with mocked boundaries; no changes to runtime balance merge or fetch behavior shipped to consumers.

Overview
Adds AssetsController.stale-balance-scenarios.integration.test.ts, an integration suite that runs the real AssetsController with assetsAccountsApiV6: true and exercises all 12 stale-balance scenarios from the accounts API v6 decision doc (Solana snap failures/skips, BNB Chain RPC fallback when v6 marks a chain unprocessed, Account Activity live overlays/malformed rows, and staked ETH across mainnet + Hoodi after unlock and a staking tx).

Supporting changes introduce a __fixtures__/stale-balance/ tree: real HTTP captures for Accounts/Tokens/Prices APIs wired through mockStaleBalanceApis, mutable mock EVM RPC (Multicall3 aggregate3, failing tokens, staking reads), Solana keyring snap handlers, wallet/account builders, and messenger registration for BSC/mainnet/Hoodi networks. getIgnoringCase is added to test-utils for case-insensitive balance assertions, and tsc-suppressions.json picks up suppressions for fixture/test typing.

There is no production logic change in this PR—only tests, fixtures, and type suppressions.

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[Kriys94]

Mainly looked packages/assets-controller/src/AssetsController.stale-balance-scenarios.integration.test.ts and that looks good to me 👍

[Prithpal-Sooriya]

Mainly looked packages/assets-controller/src/AssetsController.stale-balance-scenarios.integration.test.ts and that looks good to me 👍

Thanks @Kriys94 - yep this was the main file that needed review. Good call on realistic data capture - I'm re-executing this now.

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[Prithpal-Sooriya]

While re-capturing the fixtures I also fixed the newly-failing Lint (lint:tsc:check) job (heads d028245 and earlier):

• lint:tsc:check was added on main after this branch's last sync. It runs repo-wide tsc --build tsconfig.lint.json and compares every error against the root tsc-suppressions.json.
• This suite's fixture and test files carry 14 latent test-file type errors that no previous CI job checked (yarn build excludes test files, and Jest does not type-check), so the new gate flagged them as unsuppressed.
• None of them are caused by the fixture rebuild: 9 sit in the suite's own harness code (messenger.ts, provider.ts, staleBalanceWallet.ts, the integration test) that this change never touched; the 5 in the nock-wiring index.ts are the same pre-existing pattern (loose stub values vs as const fixture literal types), only now spelled with the new capture's literals.

Fix (8bef618): synced main to pick up the tooling and suppressions file, then recorded the 14 errors with the repo's own yarn lint:tsc:check --suppress-all — no source or test-behavior change. Verified locally: lint:tsc:check passes, stale-balance suite 12/12, full assets-controller package 1286/1286, lint:misc:check clean. All 346 checks green on 8bef618.

[Prithpal-Sooriya]

Follow-up on the lint:tsc:check fix: 8bef618 had recorded the 14 latent type errors in tsc-suppressions.json. Reconsidering — the suppressions file is a ratchet for pre-existing debt, so a brand-new suite shouldn't add to it. 3ab8cb0 fixes the errors in place instead and drops those suppression entries (the file is now identical to main):

• V6BalanceEntry now has a structural type instead of being inferred from the BSC capture's literals (which is what rejected the mainnet rows, the balance-replacement spreads, and the zero-balance stub).
• mockStaleBalanceApis options are now annotated StaleBalanceApiMutations (shared with the v6 mock; they previously inferred never[]/{} defaults).
• The wallet builders complete account metadata with keyring/importTime defaults, mirroring createMockInternalAccount.
• The transactionConfirmed payload completes its TransactionMeta fields (id, networkClientId, status, time) — the listener only reads chainId/txParams, so behavior is unchanged.
• defaultAbiCoder.encode's result is cast to Hex (it always returns hex, but is typed string).

@ts-expect-error remains in exactly two intentional places: the malformed-row scenario (the rows deliberately violate BalanceUpdate) and Hoodi's native-asset identifier, which uses the zero-address ERC-20 fallback the extension itself applies to chains missing from the slip44 map (see NATIVE_ASSETS).

Verified: lint:tsc:check clean with no new suppressions, suite 12/12, full assets-controller package 1286/1286, lint:misc:check + lint:oxlint clean, and all checks green on 3ab8cb0.